<s>
Squitter	B-Algorithm
refers	O
to	O
random	O
pulses	O
,	O
pulse-pairs	O
and	O
other	O
non-solicited	O
messages	O
used	O
in	O
various	O
aviation	O
radio	O
systems	O
 '	O
signal	O
maintenance	O
.	O
</s>
<s>
Squitter	B-Algorithm
pulses	O
were	O
originally	O
,	O
and	O
are	O
still	O
,	O
used	O
in	O
the	O
DME/TACAN	O
air	O
navigation	O
systems	O
.	O
</s>
<s>
Squitter	B-Algorithm
pulses	O
,	O
because	O
of	O
their	O
randomness	O
and	O
identical	O
appearance	O
to	O
standard	O
reply	O
pulse-pairs	O
,	O
appear	O
the	O
same	O
as	O
unsolicited/unsynchronised	O
replies	O
to	O
other	O
interrogating	O
aircraft	O
.	O
</s>
<s>
Squitter	B-Algorithm
was	O
first	O
used	O
in	O
the	O
original	O
IFF	B-Device
systems	O
.	O
</s>
<s>
Primarily	O
,	O
squitter	B-Algorithm
is	O
used	O
to	O
maintain	O
a	O
regular	O
signal	O
from	O
the	O
ground	O
beacon	O
.	O
</s>
<s>
In	O
the	O
Mode	O
S	O
secondary	O
surveillance	O
radar	O
system	O
,	O
the	O
term	O
is	O
used	O
to	O
describe	O
messages	O
that	O
are	O
unsolicited	O
downlink	O
transmissions	O
from	O
an	O
automatic	B-Application
dependent	I-Application
surveillance-broadcast	I-Application
(	O
ADS-B	B-Application
)	O
Mode	O
S	O
transponder	O
system	O
.	O
</s>
<s>
Mode	O
S	O
transponders	O
transmit	O
acquisition	O
squitter	B-Algorithm
(	O
unsolicited	O
downlink	O
transmissions	O
)	O
to	O
permit	O
passive	O
acquisition	O
by	O
interrogators	O
with	O
broad	O
antenna	O
beams	O
,	O
where	O
active	O
acquisition	O
may	O
be	O
hindered	O
by	O
all-call	O
synchronous	O
garble	O
.	O
</s>
